The present invention relates to a lectin protein isolated from the Korean marine crab, Philyra pisum in the family Leucosiidae, a process for preparing the same and the use thereof. More specifically, the present invention relates to a lectin designated PPA (Philyra pisum agglutinin) that is a protein component isolated from the hemolymph of Korean marine crab Philyra pisum and specifically binds to N-glycolylneuraminic acid, a process for isolating and purifying the same, and the various uses of the PPA based on its biological activities.
In general, differentiation and growth as intercellular recognition and interaction processes in a normal living body not affected by a disease are considered as essential processes. Abnormality occurring in differentiation and growth may causes incomplete development, malformation or cancer in cells. With recent understanding at the gene and protein levels, carbohydrates on the cell membrane surface have lately been given great attention as a substance that enables the understanding of the vital phenomenon at the molecular level. As an example thereof, it is reported that structural change of carbohydrate on the cell membrane surface is observed in the process of malignant degeneration of animal cells by viruses and the like, and that the abnormality of carbohydrates on the cell membrane commonly occurs in most of cancer cells. A dramatic change of carbohydrate structure has also been reported in development and differentiation processes.
Intercellular recognition occurs by way of carbohydrates on the cell membrane surface. In order to mediate this process, molecules specifically recognizing the carbohydrates should exist on the cell membrane surface. For example, a carbohydrate-binding protein such as lectin is necessary on the cell membrane surface.
Philyra pisum, which belongs to the family of Leucosiidae, is distributed throughout the mud areas of the west coast in Korea and characterized by a habit of walking forward unlike the other crabs, and is slow and feigns death when touched. Philyra pisum has not been used for food, and thus, biochemical research thereon is very poor.